Copper metal film, method for producing same, copper metal pattern, conductive wiring line using the copper metal pattern, copper metal bump, heat conduction path, bonding material, and liquid composition

Abstract

Disclosed are: a copper metal film which has good adhesion to a substrate, low volume resistivity, and good deep-part metal properties; and a method for producing a copper metal film, wherein the copper metal film can be produced by reducing a substrate to a deep part thereof without damaging the substrate. Specifically disclosed is a copper metal film obtained by treating a copper-based particle deposition layer containing both copper oxides and a metallic transition metal or alloy, or a transition metal complex containing a metal element, with gaseous formic acid and/or formaldehyde heated to 120° C. or higher. The copper oxide is preferably copper (I) oxide and/or copper (II) oxide. The transition metal, alloy or metal complex are preferably a metal selected from the group consisting of Cu, Pd, Pt, Ni, Ag, Au and Rh, an alloy containing the metal, or a complex containing the metal element, respectively.

The invention claimed is: 
     
       1. A method for producing a copper metal film, comprising: producing gaseous formic acid by converting liquid formic acid to gaseous formic acid, and treating a copper-based particle deposition layer containing both copper oxide and a metallic transition metal or alloy, or a transition metal complex containing a metal element, with the gaseous formic acid converted from liquid formic acid, the gaseous formic acid being heated to 120° C. or higher, wherein a ratio of copper oxide to the metallic transition metal or alloy or the transition metal complex containing a metal element in the copper-based particle deposition layer is 9:1 to 100,000:1. 
     
     
       2. The method for producing a copper metal film according to  claim 1 , wherein the copper oxide comprises cuprous oxide and/or cupric oxide. 
     
     
       3. The method for producing a copper metal film according to  claim 1 , wherein the transition metal, the alloy, and the transition metal complex are a metal selected from the group consisting of Cu, Pd, Pt, Ni, Ag, Au and Rh, an alloy containing the metal, and a complex containing the metal element, respectively. 
     
     
       4. The method for producing a copper metal film according to  claim 1 , wherein as the copper oxide, and the metallic transition metal or alloy, or the transition metal complex containing a metal element, the copper metal film contains particles comprising a core/shell structure in which the core part is formed of the transition metal or alloy, and the shell part is formed of the copper oxide. 
     
     
       5. The method for producing a copper metal film according to  claim 1 , wherein the metallic transition metal is copper metal obtained by reducing a portion of the copper-based particle deposition layer. 
     
     
       6. The method for producing a copper metal film according to  claim 5 , wherein the technique for reducing a portion of the copper-based particle deposition layer is any one of (1) a hot wire method atomic hydrogen treatment, (2) a surface wave plasma treatment, (3) an RF plasma treatment, (4) heating under hydrogen, (5) a treatment using a treatment liquid which contains, in a single solution, both an agent which ionizes or complexates copper oxide, and a reducing agent which reduces copper ions or a copper complex to copper metal, but does not contain copper ions, and (6) an atomic hydrogen treatment through ultraviolet irradiation. 
     
     
       7. The method for producing a copper metal film according to  claim 1 , wherein the copper-based particle deposition layer is a layer obtained by depositing a particle mixture prepared by mixing particles formed of the metallic transition metal or alloy, or the transition metal complex containing a metal element, with copper oxide particles at an arbitrary ratio. 
     
     
       8. The method for producing a copper metal film according to  claim 1 , wherein the copper-based particle deposition layer is a layer obtained by depositing a particle mixture prepared by mixing particles formed of the metallic transition metal or alloy, or the transition metal complex containing a metal element, with particles comprising a core-shell structure in which the core part is formed of the metal and the shell part is formed of copper oxide, and with copper oxide particles, at an arbitrary ratio. 
     
     
       9. The method for producing a copper metal film according to  claim 1 , wherein the copper-based particle deposition layer is a layer obtained by depositing one or more layers containing copper oxide particles, on a layer obtained by depositing particles formed of the metallic transition metal or alloy, or the transition metal complex containing a metal element, with the layers being in contact. 
     
     
       10. The method for producing a copper metal film according to  claim 1 , wherein the copper-based particle deposition layer is a layer obtained by laminating a layer containing the metallic transition metal or alloy, or the transition metal complex containing a metal element, on a layer obtained by laminating one or more layers containing copper oxide particles. 
     
     
       11. The method for producing a copper metal film according to  claim 1 , wherein the copper-based particle deposition layer is a layer obtained by laminating one or more layers containing copper oxide particles, on a film containing the metallic transition metal or alloy, or the transition metal complex containing a metal element. 
     
     
       12. The method for producing a copper metal film according to  claim 1 , wherein the treating of the copper-based particle deposition layer with gaseous formic acid heated to 120° C. or higher comprises forming gaseous formic acid by converting liquid formic acid to gaseous formic acid at a temperature of 120° C. or higher and then leading the gaseous formic acid at a temperature of 120° C. or higher to the copper-based particle deposition layer. 
     
     
       13. The method for producing a copper metal film according to  claim 1 , wherein a ratio of copper oxide to the metallic transition metal or alloy or the transition metal complex containing a metal element in the copper-based particle deposition layer is 10:1 to 10,000:1.